Section 61. A person shall not have an abatement of a tax imposed upon his personal property subject to taxation, except as otherwise provided, unless he has brought in to the assessors a list of his personal estate as required by section 29 and complied with any requests by the assessors to examine books, papers, records and other data under section 31A. If such a list of his personal estate is not filed within the time specified in the notice required by said section 29 or the person has not complied with any requests by the assessors to examine books, papers, records and other data under said section 31A, no part of the tax assessed on the personal estate shall be abated unless the applicant shows to the assessors a reasonable excuse for the delay, or unless such tax exceeds by fifty per cent the amount which would have been assessed on such estate, if the list had been seasonably brought in, and in such case only the excess over such fifty per cent shall be abated. A person applying for an abatement of a tax on real estate may have an abatement although no list of the owner’s estate was brought in as required by the said notice; provided, that in any application for an abatement of such a tax the applicant shall include a sufficient description in writing of the particular real estate as to which an abatement is requested.